Patent document 1 teaches a compressor comprising a compressing mechanism, a discharge chamber, a housing accommodating the compressing mechanism and the discharge chamber, a discharge port communicating with the discharge chamber through a discharge passage and also with an external refrigerant circuit, a muffler formed by an expanded space disposed on the discharge passage, and a check valve disposed on the discharge passage, wherein the check valve is disposed in an accommodation chamber formed in the housing and adjacent to the discharge chamber.
In the aforementioned compressor, the check valve prevents back flow of high-pressure refrigerant gas from the external refrigerant circuit to the compressor during the stop period of the compressor.
Patent document 1: Japanese Patent Laid-Open Publication No. 11-315785